#include <iostream>

using namespace std;

double vals[] = {10.1, 12.6, 33.1, 24.1, 50.0};

double& setValues(int i) {
    double& ref = vals[i];
    return ref;   // 返回第 i 个元素的引用，ref 是一个引用变量，ref 引用 vals[i]


}

// 要调用上面定义函数的主函数
int main () {

    cout << "改变前的值" << endl;
    for ( int i = 0; i < 5; i++ ) {
        cout << "vals[" << i << "] = ";
        cout << vals[i] << endl;
    }

    setValues(1) = 20.23; // 改变第 2 个元素
    setValues(3) = 70.8;  // 改变第 4 个元素

    cout << "改变后的值" << endl;
    for ( int i = 0; i < 5; i++ ) {
        cout << "vals[" << i << "] = ";
        cout << vals[i] << endl;
    }
    return 0;
}